The present invention relates to power tongs of the type commonly used to work the threaded connections of tubular goods commonly used in oil field well drilling. It is often necessary in oil field drilling operations to make and break threaded connections between joints of pipe which are used in serial order to make up drill strings, casing strings, and the like. A typical power tong includes a mechanism for gripping the external surface of a pipe section and rotating the pipe section while the pipe section to which it is connected is held stationary. The current state of the art in power tong construction is represented by the U.S. Pat. No. 4,084,453 issued to Eckel. This device functions well enough, but improvements are currently sought to better serve in the maintainability and durability of the parts most subject to wear. The parts most subject to wear are the pipe gripping dies and the means employed to force them into the pipe surface to achieve a turning ability.
Accordingly, an object of the present invention is to provide a power tong for making up and breaking apart joints of well bore tubular goods, and the like, having an improved pipe gripping mechanism and a simplified means for actuating the gripping mechanism.
It is another object of this invention to reduce the cam surface costs required to drive the pipe gripping dies into contact with the pipe surface.
It is yet another object of this invention to provide pipe gripping dies which require radial loads in a direction less inclined to strain the frame of the power tong system.
These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification, including the attached drawings and appended claims.